As networks continue to evolve, many network operators are deploying infrastructure for supporting both Internet Protocol (IP) television (TV) service and Internet access service. In general, a network supporting both IP TV and Internet access requires a unidirectional connection for broadcasting IP TV data from an IP TV service provider to a DSLAM serving the associated end users, and a bidirectional connection from the DSLAM serving the end user to the IP point-of-presence (POP) for the Internet access service. Alternatively, rather than a bidirectional connection for the Internet access service, the Internet access service may be provided using a multicast connection which provides both the IP TV service and the Internet access service.
In such a configuration, the network includes one multicast connection from each service provider to the DSLAMs and one unicast connection from each DSLAM to each service provider. In other words, the network must support multicast connectivity from the service providers to the DSLAMs and unicast connectivity from DSLAMs to the service providers. In existing configurations, an Ethernet network is used for interconnecting the service providers and the DSLAMS which serve the associated end users.
In one configuration, an Ethernet switch interconnects the service providers and the DSLAMS such that there is a bidirectional connection between each service provider and the Ethernet switch and a bidirectional connection between the Ethernet switch and each DSLAM for each service provider. In such a configuration, different service providers may share a connection using an Ethernet-based virtual local area network (VLAN). Disadvantageously, this configuration requires replication of the multicast IP TV service traffic at the Ethernet switch, thereby resulting in network bandwidth inefficiency when replicated Ethernet frames follow the same path through the network.
In another configuration, Ethernet frame replication may be performed further downstream by deploying additional Ethernet switches between the Ethernet switch associated with the service providers and the DSLAMs associated with the end users, thereby eliminating network bandwidth inefficiency. Disadvantageously, however, this configuration requires additional Ethernet switching capacity and may require use of the Spanning Tree Protocol for protection. In one such configuration, the additional Ethernet switches may be deployed for aggregating the traffic of the DSLAMs (i.e., a hub-and-spoke configuration in which the hub Ethernet switch is directly connected to the service providers and the spoke Ethernet switches are directly connected to the DSLAMs). Although this configuration does not require use of Spanning Tree Protocol, disadvantageously, this configuration does not eliminate the bandwidth inefficiency.